As is commonly known, turbochargers and superchargers are used to boost an engine of a motor vehicle by compressing air prior to being received by cylinders of the engine. When the air is compressed by the turbocharger or the supercharger, the air is heated and a pressure of the air is increased. However, it is desirable for the air entering the engine, such as a diesel engine or a gasoline engine, to be cooled after exiting the turbocharger or the supercharger because cooler air will have an increased density that improves an efficiency of the engine. In certain situations, the cooling of the air may also facilitate engine management and eliminate the danger of pre-detonation of the air and a fuel prior to a timed spark ignition and militate against excessive wear or heat damage to an engine block of the engine.
Charge air coolers such as water-cooled charge air coolers (WCAC) can be used in the motor vehicle to cool the air that has been compressed by the turbocharger or the supercharger prior to entering the engine. Typically, for application specific needs such as space constraints in a vehicle, for example, WCACs utilize a coolant from a low temperature (LT) coolant circuit separate from a high temperature (HT) engine coolant circuit. The LT coolant circuit includes a designated secondary radiator to cool the coolant flowing therethrough. As the compressed air flows through the WCAC, heat is transferred between air compressed by the turbocharger or the supercharger and the coolant from the LT coolant circuit. However, the coolant from the LT coolant circuit may not effectively cool or control the compressed air to desired temperatures. For example, at high levels of turbocharger or supercharger boost with ambient air temperatures, maximum performance is required from the WCAC and a desired system performance may be limited by the LT coolant circuit.
To solve the problem of limited performance due to the LT coolant circuit, some prior art solutions have relied on increasing the size of the secondary radiator of the LT coolant circuit, which may occupy undesired space and/or decrease engine performance efficiency. Other solutions incorporate WCACs with multi-staged or cascaded cooling. The WCAC with multi-stage cooling utilizes a coolant from more than one source. For example, the WCAC with multi-stage cooling may incorporate the coolant from the LT coolant circuit and the coolant from the HT engine coolant circuit. The coolant from both the LT coolant circuit and the HT engine coolant circuit facilitates cooling the compressed air to desired temperatures so system performance and efficiency of the WCAC, and accordingly the engine, is maximized.
However, a WCAC with multi-staged cooling generally employs more than one cooler unit or heat exchange core: one for receiving the coolant from the HT engine coolant circuit and one for receiving the coolant from the LT coolant circuit. Additionally, the WCAC's with multi-staged cooling may include tube-style cooling units or heat exchange cores. These types of WCACs can become expensive and complex due to an increase in required components, may not meet package space requirements, and may lack desired durability.
It would therefore be desirable to provide a charge air cooler with integrated multi-stage cooling that minimizes manufacturing costs, minimizes complexity, maximizes durability, and maintains package size requirements, while maintaining or increasing a performance and an efficiency of the charge air cooler.